Scientists got diamond's melting point wrong by more than 1,000 degrees, crushing new laser experiment reveals

Key Points:

• Scientists used powerful ultraviolet lasers to melt synthetic diamond samples, achieving more precise measurements of diamond's melting point and finding it to be over 1,300°F (700°C) lower than previously recorded.
• The new melting temperature aligns with theoretical predictions, resolving a longstanding discrepancy between experimental data and models regarding diamond's melting behavior under extreme conditions.
• X-ray diffraction showed that diamond does not transform into another solid carbon form before melting, though researchers suggest multiple shocks might induce such a phase change, which is relevant for nuclear fusion research.
• The study revealed that at pressures between 660 and 1,060 gigapascals and temperatures around 12,140°F (6,727°C), diamond coexists as solid chunks floating in metallic liquid carbon, a dense and electrically conductive form.
• These findings improve understanding of diamond's behavior under extreme conditions, aiding nuclear fusion development and providing insights into the interiors and carbon cycles of ice giant planets like Uranus and Neptune.